1. Field of the Invention
The present invention relates to a water proof crimping terminal and a crimping method of a water proof crimping terminal in which an adhesion of a core wire crimping part of the crimping terminal is improved to prevent an entry of water to a core wire part so that an amount of application of an anti-corrosive resin material to the core wire crimping part is reduced.
2. Description of the Related Art
Usually, in a crimping and connection of a terminal made of a copper alloy and an insulating coated electric wire having a core wire part made of aluminum, which are dissimilar metals, in order to prevent a galvanic corrosion (a dissimilar metal contact corrosion) occurring when water sticks to the crimping part of the core wire part and the terminal, various water proof units are proposed.
For instance, according to the disclosure of JP-A-2010-108829 (FIG. 1 to FIG. 4), as shown in FIGS. 5(a) and 5(b), a UV curing resin 53 resin 53 is applied to core wire parts exposed in front and rear parts of a pair of right and left core wire crimping pieces 52 of a terminal 51 to prevent the entry and adhesion of water to the core wire parts.
In FIGS. 5(a) and 5(b), reference numeral 54 designates an insulating coated crimping piece of the terminal 51 made of a copper alloy, 55 similarly designates a female type electric contact part and 56 designates an insulating coated part of an aluminum electric wire, respectively. JP-A-2010-108829 (FIG. 1 to FIG. 4 ) also discloses a form in which not only the front and rear parts of the core wire crimping pieces 52, but also entire parts of the core wire crimping pieces 52 and an entire part of the coated crimping piece 54 with a resin layer 53.
JP-A-7-73950 (FIG. 5, FIG. 8) discloses one example, not to waterproof, but to prevent an expansion of a core wire crimping part due to a thermal expansion of a core wire part of an electric wire, that one core wire crimping piece (a wire barrel) is formed to be longer than the other core wire crimping piece (a wire barrel), an end part of the one core wire crimping piece is folded outward to form a stepped part inside, both the core wire crimping pieces are overlapped and an upward bent end part of the other (inside) core wire crimping piece is engaged with the stepped part.
Further, the JP-A-7-73950 (FIG. 5, FIG. 8) discloses another example that an end part of a longer core wire crimping piece of an outer side is folded outward to form inside a protruding surface which protrudes inward and a shorter core wire crimping piece of an inner side is bent inward to form a recessed surface of an outer side and the protruding surface is engaged with the recessed surface.
However, in the above-described usual water proof structure of the crimping terminal shown in FIGS. 5(a) and 5(b) and disclosed in JP-A-2010-108829 (FIG. 1 to FIG. 4), there is a fear that when a gap is occasionally formed in a joint surface 56 between the a pair of core wire crimping pieces 52, water may enter the core wire parts inside the core wire crimping pieces 52 from the gap. To cancel this fear, the entire parts of the a pair of core wire crimping pieces 52 need to be covered with the resin material 53, and accordingly, there is possibility in that much time may be required to cure the resin material 53.
Further, in the usual crimping terminal disclosed in the JP-A-7-73950 (FIG. 5, FIG. 8), there is possibility in that since the longer core wire crimping piece of the outer side is folded outward or the shorter core wire crimping piece of the inner side is bent inward, a core wire accommodating area of the inner side is reduced to apply an excessive compressive deformation to a core wire part.